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WO1993011441A1 - Ameliorations apportees dans les essais de resonance quadripolaire nucleaire - Google Patents

Ameliorations apportees dans les essais de resonance quadripolaire nucleaire Download PDF

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Publication number
WO1993011441A1
WO1993011441A1 PCT/GB1992/002254 GB9202254W WO9311441A1 WO 1993011441 A1 WO1993011441 A1 WO 1993011441A1 GB 9202254 W GB9202254 W GB 9202254W WO 9311441 A1 WO9311441 A1 WO 9311441A1
Authority
WO
WIPO (PCT)
Prior art keywords
pulses
series
echo
nqr
responses
Prior art date
Application number
PCT/GB1992/002254
Other languages
English (en)
Inventor
John Alec Sydney Smith
Julian David Shaw
Original Assignee
British Technology Group Limited
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by British Technology Group Limited filed Critical British Technology Group Limited
Priority to JP5509975A priority Critical patent/JPH07501886A/ja
Priority to EP92924785A priority patent/EP0615622A1/fr
Priority to US08/244,487 priority patent/US5491414A/en
Publication of WO1993011441A1 publication Critical patent/WO1993011441A1/fr

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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R33/00—Arrangements or instruments for measuring magnetic variables
    • G01R33/20—Arrangements or instruments for measuring magnetic variables involving magnetic resonance
    • G01R33/44—Arrangements or instruments for measuring magnetic variables involving magnetic resonance using nuclear magnetic resonance [NMR]
    • G01R33/441—Nuclear Quadrupole Resonance [NQR] Spectroscopy and Imaging

Definitions

  • the present invention relates to a method of nuclear quadrupole resonance (NQR) testing of integral spin quantum number spin systems.
  • 14 N nuclei are present in a wide range of substances, including animal tissue, bone, food-stuffs, explosives and drugs.
  • the nature and disposition of the electrons and atomic nuclei produce an electric field gradient which modifies the nuclear energy levels to such an extent that measurements of NQR effects can indicate not merely the nuclei which are present but also their chemical environment, thus indicating specific substances or types of substances in any tested sample.
  • a sample is irradiated with pulses or sequences of pulses of radiofrequency electromagnetic waves having a frequency which is at or very close to a resonant frequency of quadrupolar nuclei in a substance which is to be detected. If the substance is present, the irradiant energy will raise at least some of the nuclei to a higher energy level. Such nuclei will tend to return to their normal state and in doing so they will emit radiation at their resonance frequency or frequencies which can be detected as a free induction decay (f.i.d.) during a decay period after each pulse. These emissions decay at a rate which depends on two relaxation time constants, T 1 and T 2 .
  • a method of NQR testing includes the steps of applying to a sample in which selected nuclei have an integral spin quantum number a series of at least three pulses of electromagnetic waves at a single radiofrequency to excite quadrupole resonance of the selected nuclei and detecting responses at a plurality of times when echo response signals are expected to occur.
  • n 1 to N. It has also been found that there can be echo responses which occur after a delay which matches the time interval between an excitation pulse and a echo response which precedes it, for instance at times
  • ⁇ n + ( ⁇ n - 2 ⁇ 1 ) 2 ⁇ n - 2 ⁇ 1 .
  • the times when echo response signals would be expected to occur for a particular substance or class of substance can be predetermined by experimentation in a manner which will be evident to a person skilled in the art.
  • the application and detection steps take place in the absence of an applied magnetic field.
  • the i nterval between the fi rst and second pul ses of the series is different from the interval between the second and third pulses. It has now been discovered that, using such intervals, stimulated NQR echoes can be generated, with the attendant possibility of there being more echoes generated and detected than there are pulses applied. This can in turn afford the advantage of larger signal-to-noise ratio and increased sensitivity mentioned previously.
  • the pulse times ⁇ n are preferably chosen to have no common factor and so that the echo times are distinct and separated from the excitation pulse times.
  • the time intervals ( ⁇ n - ⁇ n-1 ) may be greater than those used in conventional NQR test pulse sequences; usually ( ⁇ n - ⁇ n-1 )>T 2 *, where T 2 * is the f.i.d. time.
  • the pulses of the series are applied at times 0, ⁇ 1 and ⁇ 2 and the echo response signals are measured in periods embracing at least some of the times 2 ⁇ 1 , ⁇ 1 + ⁇ 2 , 2 ⁇ 2 and 2 ⁇ 2 - 2 ⁇ 1 . It is also preferred that ⁇ 2 >2 ⁇ 1 and ⁇ 1 and ⁇ 2 have values which make the times ⁇ 1 , ⁇ 2 , 2 ⁇ 1 , ⁇ 1 + ⁇ 2 , 2 ⁇ 2 - 2 ⁇ 1 and 2 ⁇ 2 separate and distinct from one another.
  • pulses are applied to the sample at times 0, ⁇ 1 and ⁇ 2 , it has been found that there may be little or no substantial echo response at time 2 ⁇ 2 - ⁇ 1 for integral spin quantum number systems. This fact can be used effectively to perpetuate or at least prolong the echo train.
  • a further excitation pulse may be applied at time 2 ⁇ 2 - ⁇ 1 . This will produce further echoes without suppressing or affecting the quality of detectable NQR information.
  • Figure 2 is a graphical diagram showing response signals detected in a test with the apparatus of Figure 1.
  • a radiofrequency source 10 is connected to an rf power amplifier 11.
  • the output of rf amplifier 11 is connected through switching and timing circuits 12 to r.f. coils 13 which are disposed about the sample to be tested (not shown).
  • the switching and timing circuits 12 also connect the coils 13 to a detecting and measuring circuit 14, which is also connected to a graphical recorder 15.
  • the switching and timing circuits 12 also control the timing and phase of the signals applied by the r.f. source 10 to the r.f. power amplifier 11.
  • waveform (a) represents the excitation pulse control signals applied to control a series of three single frequency excitation pulses
  • the pulse sequence was of the form 90o O - ⁇ 1 -90o O - ⁇ 2 -90° O -.
  • Each excitation pulse lasted for 20 ⁇ s and was followed by a blanking period of 200 ⁇ s; during these times the detecting circuit was not connected to the coils, to avoid overload.
  • the trace clearly shows the NQR echo responses occurring around the times 2 ⁇ 1 , ⁇ 2 + ⁇ 1 , 2x 2 - 2 ⁇ 1 , and 2 ⁇ 2 .
  • a possible response at 2 ⁇ 2 - ⁇ 1 is either very weak or is thought perhaps not to exist at all.
  • Parts 20 and 21 of the trace show the f.i.d.s after the first and third excitation pulses; the f.i.d. after the second pulse does not appear on this trace which shows the output of only one of two channels arranged to measure signals of opposite phase.
  • the excitation signals in the second pulse may be in antiphase relationship with the signals of the first and third pulses.
  • each of the echo responses is spread over a period of about 1 millisecond which is about twice the f.i.d. time constant T 2 * and is fifty times longer than the excitation pulse length.
  • the strength and duration of the echo responses are so great that by using them in addition to the f.i.d.'s the sensitivity of the tests can be greatly increased.

Landscapes

  • Physics & Mathematics (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • High Energy & Nuclear Physics (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • General Physics & Mathematics (AREA)
  • Magnetic Resonance Imaging Apparatus (AREA)
  • Investigating Or Analyzing Materials By The Use Of Electric Means (AREA)
  • Investigating Or Analyzing Materials By The Use Of Magnetic Means (AREA)
  • Geophysics And Detection Of Objects (AREA)

Abstract

Un procédé d'essais de résonance quadripolaire nucléaire consiste à appliquer à un échantillon, dans lequel des noyaux sélectionnés ont un nombre quantique de spin intégral, une série d'au moins trois impulsions d'ondes électromagnétiques au niveau d'une seule radiofréquence afin d'exciter la résonance quadripolaire des noyaux sélectionnés (forme d'onde (a)) et à détecter des réponses plusieurs fois lorsque des signaux de réponse d'écho sont sensés se produire (forme d'onde (b)).
PCT/GB1992/002254 1991-12-05 1992-12-04 Ameliorations apportees dans les essais de resonance quadripolaire nucleaire WO1993011441A1 (fr)

Priority Applications (3)

Application Number Priority Date Filing Date Title
JP5509975A JPH07501886A (ja) 1991-12-05 1992-12-04 Ｎｑｒテスト方法
EP92924785A EP0615622A1 (fr) 1991-12-05 1992-12-04 Ameliorations apportees dans les essais de resonance quadripolaire nucleaire
US08/244,487 US5491414A (en) 1991-12-05 1992-12-04 Method of nuclear quadrupole resonance testing of integral spin quantum number systems

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB919125883A GB9125883D0 (en) 1991-12-05 1991-12-05 Improvements in nqr testing
GB9125883.0 1991-12-05

Publications (1)

Publication Number Publication Date
WO1993011441A1 true WO1993011441A1 (fr) 1993-06-10

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/GB1992/002254 WO1993011441A1 (fr) 1991-12-05 1992-12-04 Ameliorations apportees dans les essais de resonance quadripolaire nucleaire

Country Status (6)

Country Link
US (1) US5491414A (fr)
EP (1) EP0615622A1 (fr)
JP (1) JPH07501886A (fr)
GB (2) GB9125883D0 (fr)
IL (1) IL103986A (fr)
WO (1) WO1993011441A1 (fr)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6411208B1 (en) 1997-06-05 2002-06-25 The United States Of America As Represented By The Secretary Of The Navy Method and apparatus for detecting a target material in a sample by pre-screening the sample for piezoelectric resonance
WO2004001452A1 (fr) * 2002-06-21 2003-12-31 Qr Sciences Limited Sequences d'impulsions permettant d'exciter la resonance nucleaire quadripole
US7109705B2 (en) 1996-08-28 2006-09-19 Btg International Limited Method of and apparatus for nuclear quadrupole resonance testing a sample
US7355400B2 (en) 2002-06-20 2008-04-08 Qrsciences Pty. Ltd. Pulse sequences for exciting nuclear quadrupole resonance
US7791342B2 (en) 2007-05-18 2010-09-07 Sauer Karen L Cancellation of ringing artifacts and far field interference in nuclear quadrupole resonance

Families Citing this family (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3954092B2 (ja) 1993-06-25 2007-08-08 アフィメトリックス インコーポレイテッド 核酸配列のハイブリダイゼーションと配列決定
GB9319921D0 (en) 1993-09-27 1998-03-18 British Tech Group Method of and apparatus for testing a sample
AU4836396A (en) 1995-02-24 1996-09-11 British Technology Group Limited Method of and apparatus for nuclear quadrupole resonance testing a sample, and pulse sequence for exciting nuclear quadrupole resonance
US5608321A (en) * 1995-12-28 1997-03-04 The United States Of America As Represented By The Secretary Of The Navy Method and apparatus for detecting target species having quadropolar muclei by stochastic nuclear quadrupole resonance
US6088423A (en) * 1998-06-05 2000-07-11 Vivid Technologies, Inc. Multiview x-ray based system for detecting contraband such as in baggage
US6104190A (en) * 1998-11-17 2000-08-15 The United States Of America As Represented By The Secretary Of The Navy Nuclear quadrupole resonance (NQR) method and apparatus for detecting a nitramine explosive
AUPQ328299A0 (en) 1999-10-06 1999-10-28 Thorlock International Limited A method and apparatus for detecting a substance using nuclear resonance
GB2389418B (en) * 2002-04-10 2006-07-26 Giles Stanley A detection device
US6922460B2 (en) * 2003-06-11 2005-07-26 Quantum Magnetics, Inc. Explosives detection system using computed tomography (CT) and quadrupole resonance (QR) sensors
AR040189A1 (es) 2003-06-11 2005-03-16 Spinlock S R L Un metodo, elementos sensores y una disposicion para la deteccion y/o analisis de compuestos que presenten, simultaneamente, resonancia cuadrupolar nuclear y resonancia magnetica nuclear o doble resonancia cuadrupolar nuclear
US10043263B1 (en) * 2011-07-05 2018-08-07 Bernard Fryshman Mobile system for explosive device detection and instant active response

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GB2200462A (en) * 1987-01-27 1988-08-03 Nat Res Dev Methods and apparatus for detecting certain compounds

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SU471825A1 (ru) * 1971-07-02 1978-08-05 Специальное Конструкторское Бюро Ордена Трудового Красного Знамени Института Радиотехники И Электроники Ан Ссср Импульсный радиоспектромер дерного квадрупольного резонанса метрового диапазона
SU757947A1 (ru) * 1978-05-04 1980-08-23 Fiz Mekh Inst Akad Nauk Устройство для измерения времени спин-спиновой релаксации 1
SU958935A1 (ru) * 1981-01-27 1982-09-15 Казанский Физико-Технический Институт Казанского Филиала Ан Ссср Способ поиска и регистрации спектров дерного квадрупольного резонанса
JPH03501303A (ja) * 1988-02-15 1991-03-22 エッセルト・メト・インターナツィオナール・プロドゥクツィオーンス・ゲーエムベーハー 磁気共鳴またはスピン共鳴現象を使用するシステムおよびマーカー
GB9106789D0 (en) * 1991-04-02 1991-05-22 Nat Res Dev Nqr methods and apparatus
US5206592A (en) * 1991-05-23 1993-04-27 Buess Michael L Detection of explosives by nuclear quadrupole resonance
US5365171A (en) * 1992-11-30 1994-11-15 The United States Of America As Represented By The Secretary Of The Navy Removing the effects of acoustic ringing and reducing temperature effects in the detection of explosives by NQR

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Non-Patent Citations (3)

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ELECTRO CONFERENCE RECORD vol. 4, 24 April 1979, LOS ANGELES US pages 1841 - 1845 J.R. GONANO 'NUCLEAR MAGNETIC RESONANCE AND NUCLEAR QUADRUPOLE RESONANCE FOR BOMB DETECTION' *
INSTRUMENTS AND EXPERIMENTAL TECHNIQUES. vol. 28, no. 2, 1 March 1985, NEW YORK US pages 426 - 428 A.A. BOGUSLAVSKII ET AL. 'AUTOMATIC NUCLEAR-QUADRUPOLE-RESONANCE MEASUREMENTS USING AN ELEKTRONIKA D3-28 MICROCOMPUTER' *
REVIEW OF SCIENTIFIC INSTRUMENTS. vol. 57, no. 3, 1 March 1986, NEW YORK US pages 393 - 403 A. BIELECKI ET AL. 'ZERO-FIELD NMR AND NQR SPECTROMETER' *

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7109705B2 (en) 1996-08-28 2006-09-19 Btg International Limited Method of and apparatus for nuclear quadrupole resonance testing a sample
US6411208B1 (en) 1997-06-05 2002-06-25 The United States Of America As Represented By The Secretary Of The Navy Method and apparatus for detecting a target material in a sample by pre-screening the sample for piezoelectric resonance
US6956476B2 (en) 1997-06-05 2005-10-18 The United States Of America As Represented By The Secretary Of The Navy Method and apparatus for detecting a target material in a sample by pre-screening the sample for piezoelectric resonance
US7355400B2 (en) 2002-06-20 2008-04-08 Qrsciences Pty. Ltd. Pulse sequences for exciting nuclear quadrupole resonance
WO2004001452A1 (fr) * 2002-06-21 2003-12-31 Qr Sciences Limited Sequences d'impulsions permettant d'exciter la resonance nucleaire quadripole
US7282913B2 (en) 2002-06-21 2007-10-16 Qrsciences Pty. Ltd. Pulse sequences for exciting nuclear quadrupole resonance
US7791342B2 (en) 2007-05-18 2010-09-07 Sauer Karen L Cancellation of ringing artifacts and far field interference in nuclear quadrupole resonance

Also Published As

Publication number Publication date
US5491414A (en) 1996-02-13
GB9125883D0 (en) 1992-02-05
IL103986A (en) 1996-05-14
GB9225438D0 (en) 1993-01-27
GB2262610B (en) 1995-06-28
EP0615622A1 (fr) 1994-09-21
JPH07501886A (ja) 1995-02-23
GB2262610A (en) 1993-06-23
IL103986A0 (en) 1993-05-13

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